Nałecz K A, Korzon D, Wawrzeńczyk A, Nałecz M J
Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa.
Arch Biochem Biophys. 1995 Sep 10;322(1):214-20. doi: 10.1006/abbi.1995.1454.
Carnitine accumulation was measured in cultured neuroblastoma NB-2a cells. This process was found partially sodium dependent and its kinetics to be a sum of a saturable transport (Km = 123 +/- 13 microM) and diffusion (D = 63 +/- 7 pmol/mg protein/min/mM). On the contrary to previous reports on neural cells, the accumulation of carnitine was found insensitive to gamma-aminobutyric acid (GABA). Measurements of carnitine accumulation in the presence of different compounds resulted in the conclusion that carnitine transport does not occur through the known systems specific toward choline and/or amino acids. For instance, an observed inhibition of carnitine transport by serine and cysteine, without any effect of alanine, excluded a possible role of ASC amino acid transport system. An involvement of a new transporter is thus postulated, specific toward compounds with a polar group in the beta position with respect to the carboxylic group.
在培养的神经母细胞瘤NB - 2a细胞中测量了肉碱的积累。发现这个过程部分依赖于钠，其动力学是可饱和转运（Km = 123 +/- 13微摩尔）和扩散（D = 63 +/- 7皮摩尔/毫克蛋白/分钟/毫摩尔）的总和。与先前关于神经细胞的报道相反，发现肉碱的积累对γ-氨基丁酸（GABA）不敏感。在存在不同化合物的情况下测量肉碱积累得出的结论是，肉碱转运不是通过已知的对胆碱和/或氨基酸特异的系统进行的。例如，丝氨酸和半胱氨酸对肉碱转运的抑制作用，而丙氨酸没有任何影响，排除了ASC氨基酸转运系统的可能作用。因此推测存在一种新的转运体，它对相对于羧基在β位带有极性基团的化合物具有特异性。
